1. Field of the Invention
This invention relates to monomers for photopolymerizable compositions, which are useful as photoresists and in other photomechanical applications.
2. Description of the Prior Art
Compositions capable of polymerization under the influence of actinic radiation to form rigid, insoluble, tough, polymer-containing structures are known. Compositions of this type are described in Plambeck, U.S. Pat. No. 2,760,863, and Chu and Cohen, U.S. Pat. No. 3,649,268. Additional photopolymerizable compositions are described in British patent specification Nos. 741,470, 786,119, 802,853, and 807,948. Photopolymerizable compositions, however, may be affected by variations in atmospheric conditions, and have a tendency to be brittle on exposure and crack upon aging, especially at relatively low humidities and temperatures.
A. B. Jennings, in U.S. Pat. No. 3,036,914, discloses photopolymerizable compositions which form flexible layers free from the disadvantages just described, by adding polyethylene oxides and linear cellulose esters to ethylenically unsaturated compounds, e.g., acrylic acid diesters of a mixture of polyethylene glycols. Such systems, however, can become less sensitive to light in storage.
Dill, in U.S. Pat. No. 3,336,418, describes the use of the acrylyloxyalkyl ester monomers as plasticizers in non-photosensitive vinyl halide polymer compositions which are pressure molded to hard, rigid material at elevated temperatures.
It is therefore desirable to have photopolymerizable compositions which, on exposure, produce flexible polymeric materials which are essentially free from brittleness and do not become substantially less sensitive to light in storage.